I read the code in cmos_failover.inc But I don’t understand that RTC_BOOT_BYTE bit 1 gets the value from bit 0, the program clear bit 0 every time. But When to set the bit0 to 1, it will make the code jump to normal image next time? I search 0x70(cmos index) in all but I cant find when set bit 0 to 1?
-----Original Message----- From: steven james [mailto:pyro@linuxlabs.com] Sent: 2003年2月20日 23:27 To: Terry B. Chen Cc: linuxbios@clustermatic.org Subject: Re: how to choice fallback or normal image?
Greetings,
Several conditions need to exist for the primary image to be used. The code looks at the RTC register to check for indication of power failure (either battery dead, or clear CMOS jumper set), then the CMOS checksum is checked. If both tests show that CMOS is valid, then check the RTC_BOOT_BYTE. First, bit 0 is moved to bit 1 and bit 0 is cleared. Then, if bit 1 is set, call the primary (normal image), That is done so that if the boot fails for some reason, it will choose the fallback image next time. It is also possible to cause a fallback boot by setting the clear CMOS jumper.
The RTC_BOOT_BYTE is not included in the checksum since it will be changed wi8th every boot.
Note that on some boards, the CMOS checksum is skipped.
G'day, sjames
The RTC_BOOT_BYTE
On Thu, 20 Feb 2003, Terry B. Chen wrote:
Dear all: I was puzzled by the fallback and normal image in s2722 (e7500), I am sorry to ask so simple question. When shall we use the fallback image and when shall we use the normal image? How you control which to run? The register DRC (7c) bit 29(Init complete) seem not to be set after memory initialization complete. am I right? Thank you!
Greetings,
That is best done in Linux when it is truly known that the LinuxBIOS boot image was entirely successful (or at least successful enough that you could flash a new image if necessary).
G'day, sjames
On Fri, 21 Feb 2003, Terry B. Chen wrote:
I read the code in cmos_failover.inc But I don��t understand that RTC_BOOT_BYTE bit 1 gets the value from bit 0, the program clear bit 0 every time. But When to set the bit0 to 1, it will make the code jump to normal image next time? I search 0x70(cmos index) in all but I cant find when set bit 0 to 1?
-----Original Message----- From: steven james [mailto:pyro@linuxlabs.com] Sent: 2003��2��20�� 23:27 To: Terry B. Chen Cc: linuxbios@clustermatic.org Subject: Re: how to choice fallback or normal image?
Greetings,
Several conditions need to exist for the primary image to be used. The code looks at the RTC register to check for indication of power failure (either battery dead, or clear CMOS jumper set), then the CMOS checksum is checked. If both tests show that CMOS is valid, then check the RTC_BOOT_BYTE. First, bit 0 is moved to bit 1 and bit 0 is cleared. Then, if bit 1 is set, call the primary (normal image), That is done so that if the boot fails for some reason, it will choose the fallback image next time. It is also possible to cause a fallback boot by setting the clear CMOS jumper.
The RTC_BOOT_BYTE is not included in the checksum since it will be changed wi8th every boot.
Note that on some boards, the CMOS checksum is skipped.
G'day, sjames
The RTC_BOOT_BYTE
On Thu, 20 Feb 2003, Terry B. Chen wrote:
Dear all: I was puzzled by the fallback and normal image in s2722 (e7500), I am sorry to ask so simple question. When shall we use the fallback image and when shall we use the normal image? How you control which to run? The register DRC (7c) bit 29(Init complete) seem not to be set after memory initialization complete. am I right? Thank you!
-
steven james -
Terry B. Chen